文章基本信息

标题：Tackling Polytype Queries in Inconsistent Databases: Theory and Algorithm
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作者：Xie, Dong ; Chen, Xinbo ; Zhu, Yan 等
期刊名称：Journal of Software
印刷版ISSN：1796-217X
出版年度：2012
卷号：7
期号：8
页码：1861-1866
DOI：10.4304/jsw.7.8.1861-1866
语种：English
出版社：Academy Publisher
摘要：To expand query types under a set of integrity constraints for obtaining consistent answers over inconsistent databases, a computational theory is proposed based on first-order logic. According to directed join graphs of queries and their join completeness, computational complexities of CQA are PTIME if query types are key-key, nonkey-key, incomplete key-key with acyclic join. This paper presents several algorithms to tackle a large and practical class of queries, which can obtain the rewritten queries for computing consistent answers. For a rewritable initial query, a consistent identification statement is constructed based on the join graph by recursive computation; and the statement combines with the initial query to construct a new first-order rewritten query for computing consistent answers. To acyclic self-join queries, the recursive rewriting algorithm cannot eliminate inconsistent tuples, so the initial query combines with the statement that eliminates them.
关键词：relational database;inconsistent data;consistent query answer;first-order logic;query rewriting